Fixed window assemblies, particularly rear windows in motor vehicles, are known to have a heating grid mounted on one surface of a fixed pane, the heating grid comprising a series of heating elements and bus bars electrically connecting the heating elements. A terminal is mounted on each bus bar and connects to a power source such as a battery of the motor vehicle. Resistance to the current flowing through the heating elements generates heat which warms the fixed pane and removes ice or log. However, such fixed window assemblies do not have a provision for access to the outside to allow air to circulate within the motor vehicle.
Sliding window assemblies typically have one or more sliding panes and one or more fixed panes. The sliding pane allows access to the outside of the motor vehicle. Recently, numerous substantial improvements have been made in the art of sliding window assemblies, particularly sliding window modules used in motor vehicles. See for example, commonly owned U.S. Pat. No. 5,442,880 to Gipson et al, (disclosing an innovative sliding window assembly where a plastic frame and a backplate cooperate to define a sliding pane run channel) and 5,542,214 and 5,613,323 to Buening (disclosing several significant improvements in sliding window assemblies directed toward power and flush glass sliding modules). However, where the sliding window assembly is subjected to fog and frost, particularly when positioned in the rear of the motor vehicle, it would be desirable to be able to remove the frost without resorting to ice scrapers or other mechanical techniques. This is especially true for extended cab pick-up trucks, as the rear sliding window assemblies in extended cabs are not conveniently accessible from the driver's seat. Extended cab pick-up trucks have over the past few years taken on a dramatically increasing share of the market for trucks.
Therefore it is an object of the present invention to provide a sliding window assembly with superior design having heating elements for clearing fog or frost activated for example simply by a switch, mounted, for example, on the dashboard of a motor vehicle. It is an additional object of the present invention to provide a heated sliding window assembly in which the sliding pane has heating elements which are electrically connected to fixed pane heating elements. It is an additional object, at least in certain preferred embodiments, to provide a heated sliding window module of reduced cost and complexity while enhancing manufacturability. It is another object of the present invention to provide a heated sliding window module that is highly reliable in operation.